agent-browser

agent-browser is a skill for Claude Code from majiayu000/claude-skill-registry. It costs 112 tokens per session (4,055 once invoked), scanned A, original, MIT.

A guide for creating and fixing Claude Code subagents, which are specialised AI assistants that handle defined tasks. It covers their instructions, available tools, model choice, and delegation between agents.

In plain words
What is it for?
Use it to design a new subagent, improve its system prompt and configuration, troubleshoot invocation problems, or plan agent chaining.
Why use it?
It helps when an agent behaves incorrectly, cannot access the right tools, or lacks clear instructions. It also explains when to use a subagent instead of another Claude Code feature.

Skill for Claude Code

Written for Claude Code: allowed-tools in frontmatter.

Good fit Use it to design a new subagent, improve its system prompt and configuration, troubleshoot invocation problems, or plan agent chaining.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/majiayu000/claude-skill-registry/agent-browser
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add majiayu000/claude-skill-registry --skill agent-browser
Clone the repo
git clone --depth 1 https://github.com/majiayu000/claude-skill-registry

Made for: Claude Code.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for agent-browser

README.md
[![agentmods](https://agentmods.dev/badge/skills/majiayu000/claude-skill-registry/agent-browser/github.svg)](https://agentmods.dev/skills/majiayu000/claude-skill-registry/agent-browser)
Your own site
<a href="https://agentmods.dev/skills/majiayu000/claude-skill-registry/agent-browser"><img src="https://agentmods.dev/badge/skills/majiayu000/claude-skill-registry/agent-browser/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for agent-browser

Your own site · 80×15
<a href="https://agentmods.dev/skills/majiayu000/claude-skill-registry/agent-browser"><img src="https://agentmods.dev/badge/skills/majiayu000/claude-skill-registry/agent-browser.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 112 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 4,055 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 1 finding, up to medium

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • medium MCP Rug Pull · line 4
    npx commands without a version suffix (e.g. @1.0.0) create a rug-pull risk if the upstream server is compromised and publishes a malicious update.
    Fix: Pin the version: npx @scope/[email protected]
How audits are shown
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00112 $0.04055
Opus 5 $0.00056 $0.02027
Sonnet 5 $0.00022 $0.00811
Haiku 4.5 $0.00011 $0.00405

Measured 7d ago against content hash c696b354745d, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

agent-browser scanned grade A with 1 finding against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 7d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

save cookies to a file and use `cookies set --curl <file>`. Stay on the
skills/agent/agent-browser/SKILL.md · 478 lines

How it starts

The opening of the file, as written. The whole thing — 478 lines — stays where its author put it; the contents beside it link to each section on GitHub.

agent-browser core

Fast browser automation CLI for AI agents. Chrome/Chromium via CDP, no Playwright or Puppeteer dependency. Accessibility-tree snapshots with compact @eN refs let agents interact with pages in ~200-400 tokens instead of parsing raw HTML.

Most normal web tasks (navigate, read, click, fill, extract, screenshot) are covered here. Load a specialized skill when the task falls outside browser web pages — see When to load another skill.

The core loop

agent-browser open <url>        # 1. Open a page
agent-browser snapshot -i       # 2. See what's on it (interactive elements only)
agent-browser click @e3         # 3. Act on refs from the snapshot
agent-browser snapshot -i       # 4. Re-snapshot after any page change

Refs (@e1, @e2, ...) are assigned fresh on every snapshot. They become stale the moment the page changes — after clicks that navigate, form submits, dynamic re-renders, dialog opens. Always re-snapshot before your next ref interaction.

Quickstart

# Install once
npm i -g agent-browser && agent-browser install

# Take a screenshot of a page
agent-browser open https://example.com
agent-browser screenshot home.png
agent-browser close

# Search, click a result, and capture it
agent-browser open https://duckduckgo.com
agent-browser snapshot -i                      # find the search box ref
agent-browser fill @e1 "agent-browser cli"
agent-browser press Enter
agent-browser wait --load networkidle
agent-browser snapshot -i                      # refs now reflect results
agent-browser click @e5                        # click a result
agent-browser screenshot result.png

The browser stays running across commands so these feel like a single session. Use agent-browser close (or close --all) when you're done.

Reading a page

agent-browser snapshot                    # full tree (verbose)
agent-browser snapshot -i                 # interactive elements only (preferred)
agent-browser snapshot -i -u              # include href urls on links
agent-browser snapshot -i -c              # compact (no empty structural nodes)
agent-browser snapshot -i -d 3            # cap depth at 3 levels
agent-browser snapshot -s "#main"         # scope to a CSS selector
agent-browser snapshot -i --json          # machine-readable output

Read the full file on GitHub · 478 lines

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 7d ago First seen · 478 lines · 112 tokens per session scan A c696b354745d

Subscribe to this mod's changes

agent-browser is a skill published in the GitHub repository majiayu000/claude-skill-registry (600 stars, last pushed yesterday), licensed MIT. It adds 112 tokens to every session and 4,055 once invoked, about $0.0006 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.